Locking device for dental drill hand pieces



Dec. 13, 1955 L, w, cc 2,726,449

LOCKING DEVICE FOR DENTAL DRILL HAND PIECES Filed June 9, 1954 III;,1114 .psm

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BYJL'A K 7% /,//M'/ 754* United States Patent LOCKING DEVICE FOR DENTALDRILL HAND PIECES Louis W. Tirocchi, Providence, R. 1.

Application June 9, 1954, Serial No. 435,420

2 Claims. (CI. 32-27) The present invention relates to contra-angledental drill handpieces and has particular reference to a novel lockingdevice therefor.

The usual construction for a contra-angle dental drill handpieceincludes a casing housing reduction gears and having a spindle sleevewith a central drill receiving bore, the drill being provided with anannular slot for receiving a releasable locking member. The standardtype includes a casing having a slit for receiving a pivoted lock latch,which is adapted to be swung in alignment with the drill handle forlocking the drill, and to be swung laterally through the slot forreleasing the drill. The locking latches heretofore used have been founddifiicult to manipulate with one hand, and are thus inconvenient whendrills must be quickly changed.

It is the principal object of the invention to provide a novel drilllocking latch which can be readily manipulated by the thumb when thehandpiece is being held, thus facilitating removal of one drill andinsertion of another.

Another object of the invention is to provide a drill locking latchwhich has a thumb piece extending substantially above the handpieceparts, so that the locking and unlocking operations can be carried outby touch.

A further object of the invention is to provide a simple locking latchfor replacing swivel type latches.

With the above and other objects and advantages features in view, theinvention consists of a novel arrangement of parts more fully disclosedin the detailed description following, in conjunction with theaccompanying drawings, and more specifically defined in the claimsappended thereto.

In the drawings,

Fig. 1 is a side view of a standard type of drill handpiece, equippedwith the novel locking latch;

Fig. 2 is an enlarged detail thereof, parts being broken away todisclose the locking latch and the parts associated therewith;

Fig. 3 is a top plan view of Fig. 2, parts being broken away; and

Fig. 4 is a perspective view of the novel locking latch.

It has been found desirable to provide a locking latch of the slide typefor replacement of the standard type swivel latch, and to form the latchso that it may be readily shifted by the fingers of the hand holding thedental handpiece, whereby a simple and convenient means is afforded forrapid changing of drills.

Referring to the drawings, the illustrative dental hand ICC piece 10includes a handle 11 having a head 12 containing standard contra-anglegears, including a rotatable spindle sleeve 13 for detachably receivinga drill or burr 14 with a standard shaft key flat.

The head 12 has a cover 15 which is spaced above the body of the head toprovide a clearance slot 16, the cover having a raised portion 17 whichforms a housing 18 into which the upper end of the drill 14 extends,whereby the annular lock groove 19 provided at the upper end of thedrill is positioned in alignment with the clearance slot.

A locking latch 20 of resilient metal is slidably positioned in theclearance slot, and includes a fiat body portion 21 having an elongatedopening 22, whereby a set screw 23, see Fig. 2, may extend through asuitable opening in the cover and loosely through the opening 22 tothreadedly seat in the head body; the outer end 24 of the latch bodyportion has a U-shaped slide recess 25 which is adapted to seat into theannular drill lock groove sides when the latch 20 is pushed forwardly;the inner end 26 of the latch body portion is extended into a roll 27 ofsubstantial size, the axis of the roll 27 being in line with the planeof the latch body portion, whereby the roll seats into the usual reducedhandle portion 28 and extends above and below the head cover, asillustrated in Fig. 2, and is resiliently pressed upwardly by contactinghandle portion. If desired, the body portion of the latch may beprovided with a small oil hole 29 to receive lubricating oil. The roll27 is preferably concave on its lower surface 30, to conform to thecurvature of the reduced handle portion 28 for resisting side movement.

When the dentist grasps the handpiece in the usual manner, the thumb isin a position to extend over the latch roll for pulling the latch backto release the drill, whereby the free hand of the dentist is availableto get the released drill and to replace it with a new drill; the thumbthen pushes the roll forwardly to lock the drill in place.

Although I have disclosed a specific embodiment of the invention, it isobvious that changes in the size, shape and proportion of the parts inaccordance with different sizes, shapes and proportions of hand pieces,may be made without departing from the spirit and scope of the inventionas defined in the appended claims.

I claim:

1. A locking latch for a dental contra-angle hand piece having a reducedcylindrical handle portion, having a fiat body portion, an elongatedopening in said body portion, a U-shaped slide recess at one end of thebody portion, and a roll at the other end of the body portion, said rollhaving its axis in the plane of the body portion and being of a size toextend substantially above and substantially below the plane of the bodyportion, the roll being concave on its lower surface to conform to thecurvature of the handle portion.

2. In the locking latch of claim 1, said body portion having an oilhole.

References Cited in the file of this patent UNITED STATES PATENTS

